Commit b938eace authored Apr 30, 2015 by David Hildenbrand Committed by Christian Borntraeger May 08, 2015

KVM: s390: fix external call injection without sigp interpretation



Commit ea5f4969 ("KVM: s390: only one external call may be pending
at a time") introduced a bug on machines that don't have SIGP
interpretation facility installed.
The injection of an external call will now always fail with -EBUSY
(if none is already pending).

This leads to the following symptoms:
- An external call will be injected but with the wrong "src cpu id",
  as this id will not be remembered.
- The target vcpu will not be woken up, therefore the guest will hang if
  it cannot deal with unexpected failures of the SIGP EXTERNAL CALL
  instruction.
- If an external call is already pending, -EBUSY will not be reported.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # v4.0
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

parent 5ebe6afa

arch/s390/kvm/interrupt.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1061,7 +1061,7 @@ static int __inject_extcall(struct kvm_vcpu vcpu, struct kvm_s390_irq irq)
		if (sclp_has_sigpif())
		return __inject_extcall_sigpif(vcpu, src_id);

		if (!test_and_set_bit(IRQ_PEND_EXT_EXTERNAL, &li->pending_irqs))
		if (test_and_set_bit(IRQ_PEND_EXT_EXTERNAL, &li->pending_irqs))
		return -EBUSY;
		*extcall = irq->u.extcall;
		atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);